The present invention is directed to the testing of packages bearing electrical leads (leaded packages).
Electronic systems or components, which may be in the form of integrated circuits, are frequently housed in packages having electrical leads which allow interconnection of the package contents to other circuitry. Such packages are frequently made of ceramic, in which case the conductive leads are brazed to the ceramic package.
In some cases, empty ceramic packages having no electronics inside are provided to a manufacturer, who fills them with electronics and sells the completed package. In other cases, the packages may be filled by their manufacturer. In either case, it is desirable to be able to test the adhesion of the leads to the package to ensure that the leads do not produce an open circuit during installation of the package, or during operation.
A prior art method of testing such packages involved pulling the leads to the point of failure, i.e. destructive testing. A certain number of packages in each lot would be so tested, and if a predetermined threshold number failed, the entire lot would be rejected.
A problem with the prior art is that many good packages which could be used are rejected and discarded. This is expensive and causes production delays, in that replacement packages must be provided. For example, if an electronics manufacturer is provided with empty packages from a vendor and an entire lot is rejected, it must await replacement packages before it can fill such packages with electronic modules and meet its sales or delivery commitments.
It is therefore desirable to provide a non-destructive method by which every package can be tested. In this way, only defective packages will be discarded, and packages which pass the test will be used.
It is an object of the present invention to provide a method and apparatus for non-destructively testing leaded packages.
In accordance with the invention, the above object is provided by employing a method of testing a leaded package comprising the steps of,
holding the package and a portion of the lead in respective stationary positions,
applying a force to the lead proximate an area where its joined to the package, and
measuring the resistance of the lead to the force.